One piece radial vane diffuser and method of manufacturing the same

ABSTRACT

A one piece radial vane diffuser constitutes an annular array of curved, radially directed vanes, surrounding the combustion area of a fuel oil burner, downstream of the nozzle, and at the downstream end of a cylinder defining a primary air flow path concentric with the nozzle. A circular sheet metal sheet is first drawn into a cone, the vanes are lanced from the cone to form a circumferential array of integral, radially directed, side by side, generally rectangular vanes linked to an annular rim at their radial outermost ends by an integral hinge. The cone is then flattened, at least in the area of the vanes, to cause the vanes to move into edge overlapping position and preferably the vanes are bent or twisted about a radial axis passing through the hinge to provide air passages between vanes of predetermined size. The vanes may be curved relative to their radial axes to effect swirling of the primary air flow.

it tates Patent Runninger 1 ONE PIECE RADIAL VANE DIFFUSER AND METHOD OFMANUFACTURING THE SAME [75] Inventor: Frederick L. Rnnninger,

l-larrisonburg, Va.

[73] Assignee: Dunham-Bush,lnc., Harrisonburg,

22 Filed: Aug. 15,1973

[21] Appl. No.: 388,669

[56] References Cited UNITED STATES PATENTS 1,991,894 2/1935 Forney239/399 3,309,027 3/1967 Chadwick et a1... 239/406 3,383,052 5/1968Qysart et al. 239/406 X 3,650,477 3/1972 Tiullikssonii ..239/399 X IFOREIGN PATENTS OR APPLICATIONS 651,400 10/1962 Canada 431/265 Nov. 5,1974 205.892 l0/l923 Great Britain ..239/406 Primary Examiner-Robert S.Ward, Jr. Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn &Macpeak [5 7 ABSTRACT A one piece radial vane diffuser constitutes anannular array of curved, radially directed vanes, surrounding thecombustion area of a fuel oil burner, downstream of the nozzle, and atthe downstream end of a cylinder defining a primary air flow pathconcentric with the nozzle. A circular sheet metal sheet is first drawninto a cone, the vanes are lanced from the cone to form acircumferential array of integral, radially directed, side by side,generally rectangular vanes linked to an annular rim at their radialoutermost ends by an integral hinge. The cone is then flattened, atleast in the area of the vanes, to cause the vanes to move into edgeoverlapping position and preferably the vanes are bent or twisted abouta radial axis passing through the hinge to provide air passages betweenvanes of predetermined size. The vanes may be curved relative to theirradial axes to effect swirling of the primary-air flow.

10 Claims, 4 Drawing Figures BACKGROUND OF THE INVENTION FIELD OF THEINVENTION This invention relates to fuel oil burners, and moreparticularly, to acne piece radial vane diffuser and its SUMMARY OF THEINVENTION The present invention is directed to forming such a radialvane diffuser from a single circular plate of sheet metal. A circular,flat sheet metal plate is first drawn into a cone, and the cone is thenlanced to form an annular outer rim and a plurality of integral,circumferentially spaced, radially directed and generally rectangularvanes joined to the rim only at their radially outermost ends by anintegral hinge. The lanced cone, at least in the area of the vanes, isflattened to cause the vanes to move into edge overlapping position.Preferably the vanes are bent at their hinges about a radial axispassing through the vanes to form air passages of predetermined size andconfiguration between vanes to control the primary air flow. Preferably,a portion of the rim adjacent the hinges is also flattened with thevanes, while the outermost peripheral portion of the rim is maintainedat right angles thereto, to assist mounting of the rim within thecylinder definingthe secondary air flow path. Further, the vanes may becurved about their radial pivot axes to cause the primary air flowpassing therethrough to spiral at the exit end of the one piecediffuser.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of acircular, flat sheet of metal forming the one piece radial vane diffusersubsequent to having at least its center drawn into conical form andlanced to form the individual vanes prior to flattening of the conicalportion of the plate.

FIG. 2 is a right hand, end elevational view of the drawn sheet from theright side of FIG. 1.

FIG. 3 is a similar, end view of the one piece diffuser formed from thesheet of FIGS. 1 and 2, after flattening of the conical portion,twisting of the vanes about their integral hinges and curving of theindividual vanes about a radial vane axis.

FIG. 4 is a vertical sectional view of the diffuser of FIG. 3 takenabout line 44.

DESCRIPTION OF THE PREFERRED EMBODIMENT joined to an annular rim 14which terminates at its periphery in a radially outwardly turned edge16. Further, subsequent to drawing at least portion 12 of the sheet 2ularly, that is, severed along severance lines 18 which define a largecentral opening 20, FIG. 2, to form a plurality of radial vanes 22defined by side edges 24 and 26, a radially inner edge 28 and a radiallyouter edge 30, the radially outer edge 30 being joined to side edge 26by a tapered edge portion 32 which acts in conjunction with theseverance lines 18 to form integral hinges 34. Hinges 34 join the vanes22 to rim portion 14, initially through a remnant annular portion 36 ofthe cone portion 12 of the diffuser sheet 10. Because the effect ofdrawing the flat circular sheet forming diffuser 10, into at least apartial cone, increases the surface area, subsequent to the lancing ofthe conical area to define the vanes 22, the flattening of at least thevanes of cone portion 12 causes the individual vanes to overlapp. Thus,as seen in FIG. 4, edge 26 of each of the vanes overlaps edge 24 of thenext succeeding vane in a clockwise direction. Simultaneous withflattening of the conical section 12, the individual vanes arepreferably twisted or bent about their hinges 34 to define flow passage30 between the individual vanes, and further, the individual vanes 26are preferably curved about a radial axis. In twisting or bending theindividual vanes 22 about a radial axis, relative to each vane, it ispreferred that the bend or twist take place about a line passing alongedge 24 of each vane which intersects end portion 32.

Preferably, as seen in FIG. 4, the finished one piece radial vanediffuser consists of a narrow circular rim which may be of a diameter onthe order of the cylindrical member (and not shown) defining the primaryair path which acts to support the one piece radial vane diffuser I0therewithin. The formerly conical portion 12 of the diffuser isflattened such that the annular portion 36 of the diffuser I0 is atright angles to mounting rim l4 and it is from this portion 36 that thecurved radial vanes 22 emanate. The effect of the curved vanes and theirspacing is to insure movement of the primary air flow into a spiral orhelical path downstream of the diffuser 10 to effect greater mixing withthe fuel oil from the nozzle and to promote excellent combustion of thefuel and air mixture downstream of diffuser 10, that is, in a directionto the left of the diffuser 10 in FIG. 4.

The diffuser may be formed of any sheet metal capable of withstandingthe high temperature effects of into conical shape, the sheet metalplate is lanced irregcombustion downstream of the nozzle but must be ofa metal permitting: the drawing of the cone from the flat sheet, thesubsequent lancing to form the individual vanes 22 forming an outercircular array, the bending or twisting of the individual vanes aboutthe integral hinges 34 and the curving of the vanes 22 about a radialaxis passing therethrough by the method of manufacture of the presentinvention.

While the invention has been particularly shown and described withreference to a preferred embodiment thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

What is claimed is:

l. A one piece radial vane diffuser comprising: a circular metal sheetincluding an annular rim, a plurality of circumferentially spaced radialvanes partially struck from said sheet and being joined to said rim attheir radially outermost ends by hinges integral with said rim, saidvanes being of a width so as to overlap at their side edges, and saidvanes being similarly twisted at said hinges, about a radial axisextending through said hinges to form air passages therebetween.

2. The radial vane diffuser as claimed in claim 1, wherein said vanescomprise sectors of said sheet and are severed therefrom except alongone side edge of said vanes at their radial outer ends, with said vanesbeing twisted about a radial axis which coincides with said one sideedge of said vanes.

3. The radial vane diffuser as claimed in claim 1, wherein the radiallyouter ends of said other side edge of each vane are tapered toward saidone side edge thereof to form said hinge.

4. The radial vane diffuser as claimed in claim 2, wherein the radiallyouter ends of said other side edge of each vane are tapered toward saidone side edge thereof to form said hinge.

5. A method of manufacturing a one piece radial vane diffuser comprisingthe steps of:

forming at least an interior portion of a circular flat sheet of metalinto a cone,

lancing the cone to form an annular outer rim and a circumferentialarray of integral, radially directed, generally rectangular vanes joinedto said rim only at their radially outermost ends, and

flattening at least that portion of said cone forming said vanes tocause said vanes to move into edge overlapping position.

6. The method of manufacturing a one piece radial vane diffuser asclaimed in claim 5, further comprising twisting said vanes about aradial axis passing through the vanes to form air passages betweenvanes.

7. The method of manufacturing a one piece radial vane diffuser asclaimed in claim 5, further comprising curving each vane about a radialaxis thereof to cause swirl of the air flow passing through the airpassages between vanes.

8. The method of manufacturing a one piece radial vane diffuser asclaimed in claim 6, further comprising curving each vane about a radialaxis thereof to cause swirl of the air flow passing through the airpassages between vanes.

9. The method of manufacturing a one piece radial vane diffuser asclaimed in claim 5, wherein the radially inner portion of said rimcoupled to said vanes, is flattened along with said vanes at rightangles to the radially outer peripheral portion of said sheet to definea circular, axially directed rim portion generally at right angles tothe vanes and said inner rim portion.

10. A method of manufacturing a one piece radial vane diffuser from aunitary sheet metal plate comprising the steps of:

drawing said flat metal plate into conical form with a cylindrical rimportion at its outer periphery,

lancing the conical portion to form an unsevered intermediate annularportion and a circumferentially array of integral, radially directedgenerally rectangular vanes joined to said intermediate annular portiononly at their radially outermost ends by an integral hinge portion, and

flattening the portion of said cone including said vanes and saidintermediate annular portion to form an annular portion at right anglesto said cylindrical rim and a plurality of circumferentially spaced edgeoverlapping vanes and curving said vanes about radial axes passingthrough the vanes to form axial air passages therebetween ofpredetermined size and configuration,

whereby, the air swirls as it exits the air passages be tween the vanesand enters the axial passage determined by said cylindrical rim.

1. A one piece radiaL vane diffuser comprising: a circular metal sheetincluding an annular rim, a plurality of circumferentially spaced radialvanes partially struck from said sheet and being joined to said rim attheir radially outermost ends by hinges integral with said rim, saidvanes being of a width so as to overlap at their side edges, and saidvanes being similarly twisted at said hinges, about a radial axisextending through said hinges to form air passages therebetween.
 2. Theradial vane diffuser as claimed in claim 1, wherein said vanes comprisesectors of said sheet and are severed therefrom except along one sideedge of said vanes at their radial outer ends, with said vanes beingtwisted about a radial axis which coincides with said one side edge ofsaid vanes.
 3. The radial vane diffuser as claimed in claim 1, whereinthe radially outer ends of said other side edge of each vane are taperedtoward said one side edge thereof to form said hinge.
 4. The radial vanediffuser as claimed in claim 2, wherein the radially outer ends of saidother side edge of each vane are tapered toward said one side edgethereof to form said hinge.
 5. A method of manufacturing a one pieceradial vane diffuser comprising the steps of: forming at least aninterior portion of a circular flat sheet of metal into a cone, lancingthe cone to form an annular outer rim and a circumferential array ofintegral, radially directed, generally rectangular vanes joined to saidrim only at their radially outermost ends, and flattening at least thatportion of said cone forming said vanes to cause said vanes to move intoedge overlapping position.
 6. The method of manufacturing a one pieceradial vane diffuser as claimed in claim 5, further comprising twistingsaid vanes about a radial axis passing through the vanes to form airpassages between vanes.
 7. The method of manufacturing a one pieceradial vane diffuser as claimed in claim 5, further comprising curvingeach vane about a radial axis thereof to cause swirl of the air flowpassing through the air passages between vanes.
 8. The method ofmanufacturing a one piece radial vane diffuser as claimed in claim 6,further comprising curving each vane about a radial axis thereof tocause swirl of the air flow passing through the air passages betweenvanes.
 9. The method of manufacturing a one piece radial vane diffuseras claimed in claim 5, wherein the radially inner portion of said rimcoupled to said vanes, is flattened along with said vanes at rightangles to the radially outer peripheral portion of said sheet to definea circular, axially directed rim portion generally at right angles tothe vanes and said inner rim portion.
 10. A method of manufacturing aone piece radial vane diffuser from a unitary sheet metal platecomprising the steps of: drawing said flat metal plate into conical formwith a cylindrical rim portion at its outer periphery, lancing theconical portion to form an unsevered intermediate annular portion and acircumferentially array of integral, radially directed generallyrectangular vanes joined to said intermediate annular portion only attheir radially outermost ends by an integral hinge portion, andflattening the portion of said cone including said vanes and saidintermediate annular portion to form an annular portion at right anglesto said cylindrical rim and a plurality of circumferentially spaced edgeoverlapping vanes and curving said vanes about radial axes passingthrough the vanes to form axial air passages therebetween ofpredetermined size and configuration, whereby, the air swirls as itexits the air passages between the vanes and enters the axial passagedetermined by said cylindrical rim.